1. Field of the Invention
The present invention relates generally to medical devices and methods. More particularly, the present invention relates to medical devices, systems, and methods for determining cardiac performance characteristics based on data obtained from implanted cardiac sensors.
Intravascular and intraluminal interventions and monitoring have become essential in modern cardiology and other medical fields. Of particular interest to the present invention, a variety of implantable sensors, intravascular catheters, and other devices and systems have been developed for monitoring cardiac performance both in and outside of a medical facility.
The ability to adequately treat patients suffering from or at risk of cardiac disease can be greatly enhanced by frequent, or better still real time continuous, monitoring of cardiac function. For example, patients suffering from congestive heart failure could titrate dosages of certain medications if more information were available and/or information were available more often relating to cardiac function and how it has responded to drug treatment. Additionally, the need for surgical intervention could also be better assessed if better cardiac performance data were available.
For these reasons, it would be desirable to provide improved devices, systems, and methods for monitoring cardiac performance both in and outside of medical facilities. Such improved devices, systems, and methods should allow for measuring a variety of mechanical, biological, and chemical parameters related to cardiac performance and further to analyze calculated cardiac performance values based on such measured performance characteristics. Preferably, the devices and apparatus will include implantable sensors which transmit data to allow for periodic or continuous collection of in situ cardiac performance data. The devices and systems should further include external components for collecting the internally transmitted data and for optionally obtaining external patient data. The systems may then calculate secondary cardiac performance parameters based on the measured internal and external performance data which has been collected. At least some of these objectives will be met by the inventions described hereinafter.
2. Description of the Background Art
Catheters and implantable sensors capable of measuring various physiologic parameters in the heart and/or vasculature are described in U.S. Pat. Nos. 5,814,089; 6,328,699 B1; 6,438,408 B1; U.S. Patent Publication Nos. 2001/0053882 A1; 2001/0047138 A1; 2002/0077568 A1; 2002/0111560 A1; 2002/0151816 A1; 2002/0156417; 2002/0169445; and PCT Publication WO 02/065894 A2. The full disclosures of each of these patents and patent publications are incorporated herein by reference.